Melatonin is a type of hormone that is synthesized and secreted by the pineal gland of animals as well as in plants, although for different purposes. In animals, the substance is primarily responsible for many physiologic processes that are governed by the circadian rhythm. In plants, melatonin serves as one of the integral components of first-line defense against oxidative stress. It is also highly valued for its anti-inflammatory and antioxidant properties which are two of the clinically significant physiologic processes desired in today’s supplements and preparations for dogs. Melatonin is currently used in veterinary medicine, particularly among dogs, in the management of various canine anxiety disorders as well as other health conditions that affect some of today’s pooches.

melatonin for dogs


It is quite easy to understand why both animal experts and pet lovers alike are pretty excited about the prospects of using melatonin for their dogs. The fact that it is a natural substance synthesized by humans, dogs, and other animals can be readily interpreted as something that all living organisms need. While it is not surprising that melatonin for dogs can be used for a variety of applications, only a few conditions have been studied well enough to merit the attention of veterinary professionals. The following are the most common indications of melatonin for dogs.

  • Anxiety 

One of the well-studied clinical indications of melatonin both for human and canine populations is anxiety. Evidence shows that melatonin is effective in the management of various anxiety disorders in dogs such as separation anxiety, noise phobias, and even behavioral issues like unusual restlessness, signs of obsessive compulsive behavior, hyperactivity, and sleeplessness. While it is not clear how exactly melatonin is able to address the various manifestations associated with these conditions and behaviors, physiologists say that the answer may actually lie in the natural function of melatonin.

Because melatonin production is directly related to the body’s natural circadian rhythm, its antianxiety effects may actually stem from its inherent ability to set the body’s natural clock to sleep mode. It has been observed that the production of melatonin is increased during the night leading experts to believe that the neurohormone naturally causes the body to rest and sleep in an effort to prepare it for the various restorative processes that typically occur at night. By providing melatonin for dogs that are anxious, you are inherently increasing the level of circulating melatonin in the body, particularly the brain, where it stimulates the restorative processes to begin, shutting down all unnecessary functions in the process.

Since anxiety is largely a function of a variety of neural mechanisms, shutting these mechanisms down can lead to the suppression of the symptoms of anxiety in dogs. This leads to calmer, more relaxed, and oftentimes, more peaceful canines.

  • Insomnia

The use of melatonin as a sleeping aid has been going on for many years, long before man has started using it to alleviate their anxieties. The same mechanism of action is thought to be in play with insomnia in dogs. By elevating the amount of melatonin in the body, this naturally switches on the restorative processes and switches off all non-essential processes in the body. While it is quite difficult to say with absolute certainty that such is the case, numerous observational studies do point to one inescapable fact: melatonin can really induce sleep.

  • Canine Cushing’s Syndrome 

Canine health experts believe that melatonin can help minimize the severity of symptoms of Cushing’s syndrome in dogs. This endocrine dysfunction is usually caused by a tumor located in the pituitary gland at the base of the brain. What happens is that there is an increased secretion of the hormone known as adrenocorticotrophic hormone which targets the adrenal glands to release cortisone. One of the lesser known functions of ACTH is in the control of circadian rhythms, which, we all know by now, is a domain that is also controlled by melatonin. It is now believed that melatonin for dogs may aid its body in blocking the uptake of increased levels of cortisone.

  • Seasonal hair loss 

You might not believe it but some dogs actually do suffer from seasonal alopecia or hair loss. This is also known as flank alopecia and is typically characterized by balding on either side of the dog’s abdomen. As the name implies, it is seasonal, and thus, melatonin may help by providing the necessary stimulus that is needed to help prevent the hair from thinning out. Technically, melatonin is related to time-associated events. That is why it is active at night and passive in the day. The same principle applies to the seasons. Exactly how it helps dogs with seasonal alopecia is still poorly understood. What is sufficient for now is that dog owners will feel more confident they can turn to something more natural in managing patchy hair loss in their pooches.

Benefits of Melatonin

As we have already mentioned above, it is possible that melatonin can provide a host of benefits that we may not even be cognizant about. Nevertheless, the following benefits of melatonin for dogs are directly related to their indications.

  • Helps relieve anxiety; calms and relaxes dogs 

No owner would ever want to see his dog very anxious. While we can always train our dogs not to be anxious every time we leave the house or whenever there are unusually loud noises such as during a thunderstorm or even fireworks, the thing is that canine training typically involves a lot of hard work, dedication, commitment, and perseverance. Don’t get us wrong. We strongly advise you to train your dog. However, while you’re at it, you might want to consider giving them melatonin since it will take some time before they can successfully learn what you are training them. While waiting for the results of your canine anxiety reduction training, you can give them melatonin so they don’t have to live every moment of their lives very anxious.

  • Allows dogs to sleep a lot better 

Every living organism needs to sleep. It doesn’t really matter where or what time sleep will come, the important thing is that there should be a period in a day when your dog is able to rest its tired body, shut off anything not essential to its survival, and begin repairing and replenishing tissues and hormones. Unfortunately, if your pooch is also as insomniac as you are, it won’t be able to feel refreshed. More importantly, it will not be able to produce all of those natural substances that are synthesized only when the dog is asleep. Insomnia is robbing your dog of invaluable opportunity to really grow and develop. Thankfully, melatonin can help by switching the body’s natural body clock and set it to sleep mode.

  • Minimizes the severity of Cushing’s disease in dogs 

While not all dogs will have Cushing’s disease, those that do will greatly benefit from melatonin. This substance can reduce the severity of Cushingoid symptoms which typically includes hypertension, weight gain, irritability, fatigue, insomnia, depression, weak bones, easy bruising, and impaired immunity, among others.

  • Prevents patchy seasonal hair loss 

Unless you have a Chinese Crested breed, having a dog with balding hair simply isn’t nice to look at. You might even be frowned upon by other dog owners since balding is often a sign of poor nutrition in dogs, leading some to believe that you’re not taking care of your pooch. While it is only seasonal, at least you will feel a lot better knowing that your pooch doesn’t have to go through the balding process anymore. Perhaps even more important is what other people will say, or will not say, to you for having a dog that has complete hair.

How Melatonin Works

Discussing in detail the actual mechanism of action of melatonin will take us an entire book. So, without really going into a lot of technical detail, we will try to explain it in simpler terms.

Melatonin is a substance that synchronizes almost every single process in the body. You can look at it as a sensor that is dictated by time. Scientists call this intrinsic clockwork as the circadian rhythm or the series of events or activities that occur in the body within a full 24 hours. The theory is that everything has the proper time for its initiation and completion. For example, once light and sound are sensed by the body in the morning, it wakes everything up. When light is dimmed and sound is suppressed, the body also goes into what we call sleep state. The same thing occurs in other physiologic processes such as blood pressure whereby it is greater during the day and more subdued at night. This works for seasonal reproduction, too, whereby animals are triggered into mating and breeding. Of course, there are always members of the animal kingdom that seem prolific when it comes to reproducing. The point is that almost everything in life occurs in cycles. It has a beginning and it has an end.

We already mentioned that melatonin has been noted to be highly active during the night and less active in the day. This observation has led experts to believe that by increasing the levels of melatonin, even during the day, can help ‘switch on’ the natural physiologic effects of melatonin. What they are saying is that, by providing melatonin for dogs, we are simulating a circumstance whereby the body goes into a passive, sleep mode. This is where its anti-anxiety and sleeping aid potential are largely based upon.

Potential Side Effects

Is melatonin safe? Well, given that melatonin is a natural substance produced by living organisms themselves, humans and dogs included, it is considered to be generally safe. However, it should also be understood that since we are mimicking natural melatonin in a circumstance where it should not exert any effects, it is possible to observe any of the following side effects.

  • Confusion
  • Itching
  • Headache
  • Behavioral changes
  • Increased heart rate
  • Upset stomach
  • Changes in the female dog’s reproductive cycles
  • Sleepiness

These side effects are more related to tinkering with the natural circadian rhythms of dogs.

How Much Melatonin Can You Give a Dog?

Like all canine products, the exact melatonin dosage you can give to your dog is dependent on a variety of factors including its weight, age, and general health condition. More importantly, the indication for which melatonin is going to be used on dogs is crucial since some canine health conditions require substantially higher or even lower dosages than normal. That being said, it is critical that a veterinary consultation be obtained first before you can even start entertaining the idea of giving melatonin for dogs. Know that like anything else, there will be certain dogs that are simply not fit to take this hormone preparation. It is better that your vet ascertain first the suitability of giving melatonin to your pooch.

That said, your veterinarian will typically provide you with the following melatonin dosage recommendations.

  • Dogs that weigh less than 10 pounds can be given 1 milligram of melatonin
  • Pooches weighing 10 to 25 pounds can receive 1.5 milligrams of melatonin
  • Hounds that weigh between 26 and 100 pounds can be administered with 3 milligrams of melatonin
  • Canines that weigh more than 100 pounds can be given anywhere from 3 to 6 milligrams of melatonin

Again these dosages are for reference use only. Your veterinarian should be able to tell you exactly how much you need to give to your canine friend.

How to Give Melatonin to Your Pooch

Melatonin for dogs is available in a variety of presentations including chewable tablets, drops, pills, and even injectable implant forms. Your choice of presentation will help decide how you are going to give melatonin to your pooch.

Obviously, the less invasive approach to administering the substance is by oral route. There are some brands that come with flavorings to help in the easier administration. If the brand that you bought doesn’t come in a palatable form, then you can try masking it in your dog’s treat as a means of administration. Do supervise your dog if you do choose this route as there is a tendency of some dogs to regurgitate the tablet or pill. In case of liquid preparations, make sure your pooch swallowed every last bit of the solution.

There are also instances when sustained levels of melatonin are needed by your dog. In such cases, an injectable implant can be administered by your veterinarian. The implant is injected directly underneath the dog’s skin where it releases a steady concentration of precisely measured melatonin dose over a set period of time. This eliminates the daily administration of the substance, minimizing missed doses in the process.

sleepy puppy

How Long Does Melatonin Take to Work?

The onset of action of melatonin, unfortunately, varies from one dog to another. Even in same breeds or same age dogs, the variability can be as large as a few hours or as small as a few minutes. Generally, however, your dog should be able to experience some of the desired effects of melatonin within the first 30 minutes after administration. Some pooches may take longer than 30 minutes, some may require only 20. The point really is that no one can accurately say when melatonin will start working. If there is any consolation, you don’t have to wait a full day to see the effects on your dog.

What to Do in Case of Melatonin Overdose

We emphasized the need for consulting with your veterinarian first before making any attempts to give your pooch a melatonin dosage. The reason again is quite simple. We don’t want to risk the health and safety of our dogs on a substance that may be natural but will be used for a purpose that is not really intended to work in the specific circumstance we want it to work. Also, different dogs will react differently to such substances.

Generally, melatonin overdose is rare and usually occurs among those who did not take the time to talk to their veterinarians first. Also, while melatonin has a very rapid onset of action, it is nevertheless excreted rather slowly. This allows it to accumulate in the bloodstream. And if the next dose is administered even without fully clearing the previous dose from the body, then an overdose is most likely to occur.

Should an overdose occur, which is typically characterized by vomiting and dizziness, although seizures can also happen, there really is only one course of action to take – bring your hound to your veterinarian. Alternatively, you can also contact the poison control of ASPCA at (888) 426-4435. They can instruct you on the steps you need to do to counter the melatonin overdose.

Melatonin is a substance that is either derived from natural sources or synthesized chemically to mimic the physiologic effects of natural melatonin in the dog’s body. It is primarily indicated in the management of canine anxiety, insomnia, Cushing’s disease, and even seasonal alopecia. The benefits are all directly related to its indications. Despite being a natural substance, there are a few side effects that one needs to be aware of. Its fast onset of action but very slow elimination can lead to the development of melatonin overdose. As such, it should be given following the strict guidelines set by your veterinarian.

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Olivia Williams
Olivia is our head of content for, mum of one and a true animal lover. With 12 different types of animal in her family, it's never a dull moment. When she isn't walking the dogs, feeding the cats or playing with her pet Parrot Charlie, you will find her product researching and keeping the site freshly updated with the latest products for your pets!


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